Sericomyrmex amabilis is very common in lowland habitats throughout Costa Rica. It extends to about 800m elevation in open or seasonally dry areas, but drops out at lower elevations in close-canopy wet forest. Foraging is almost entirely nocturnal; workers are rarely seen during the day. Nests are in soil, and are difficult to locate. In some instances they make small soil craters at the nest entrance. The nest entrance hole runs horizontally beneath the soil, and is difficult to follow. I have seen foragers carrying caterpillar droppings, pieces of guava fruit (Psidium), and Cordia alliodora flowers. I collected alate queens at the La Selva blacklight on 9 January 1993. Workers are fairly common in Winkler samples of sifted litter. Workers seem to always forage on the ground; I never find them climbing up on vegetation. I have seen aggregations of dozens to hundreds of workers around nest entrances, suggesting relatively large colonies.

Comments

There are 19 species of Sericomyrmex, most of them from South America. One species is from Mexico, one from Guatemala, and one (amabilis) from Panama. All Sericomyrmex look quite similar to me. Although there is fairly pronounced geographic variation in Costa Rica, I have never found evidence of sympatric forms, nor sharp breaks or parapatric distributions of discrete forms. Sericomyrmex amabilis is the species with the nearest type locality, so I use that name for the Costa Rican material.